76 research outputs found

    Perfluoroalkyl and polyfluoroalkyl substances in the lower atmosphere and surface waters of the Chinese Bohai Sea, Yellow Sea, and Yangtze River estuary

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    Polyfluoroalkyl and perfluoroalkyl substances (PFASs), in the forms of neutral polyfluoroalkyl substances in the gas phase of air and ionic perfluoroalkyl substances in the dissolved phase of surface water, were investigated during a sampling campaign in the Bohai Sea, Yellow Sea, and Yangtze River estuary in May 2012. In the gas phase, the concentrations of neutral Sigma PFASs were within the range of 76-551 pg/m(3). Higher concentrations were observed in the South Yellow Sea. 8:2 fluorotelomer alcohol (FTOH) was the predominant compound as it accounted for 92%-95% of neutral Sigma PFASs in all air samples. Air mass backward trajectory analysis indicated that neutral Sigma PFASs came mainly from the coast of the Yellow Sea, including the Shandong, Jiangsu, and Zhejiang provinces of China, and the coastal region of South Korea. The fluxes of gas phase dry deposition, were simulated for neutral PFASs, and neutral Sigma PFASs fluxes varied from 0.37 to 23 pg/m(2)/s. In the dissolved phase of the surface water, concentrations of ionic Sigma PFASs ranged from 1.6 to 118 ng/L, with the Bohai Sea exhibiting higher concentrations than both the Yellow Sea and the Yangtze River estuary. Perfluorooctanoic acid (PFOA) was the predominant compound accounting for 51%-90% of the ionic Sigma PFAS concentrations. Releases from industrial and domestic activities as well as the semiclosed geographical conditions increased the level of ionic Sigma PFASs in the Bohai Sea. The spatial distributions of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) were different significantly. The Laizhou Bay was the major source region of PFCAs and the Yangtze River estuary was the major source of PFSAs. (C) 2017 Elsevier B.V. All rights reserved

    Per- and poly-fluoroalkyl substances (PFASs) in the urban, industrial, and background atmosphere of Northeastern China coast around the Bohai Sea: Occurrence, partitioning, and seasonal variation

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    Air samples were collected using high-volume samplers at two coastal towns on the Bohai Sea in China, 320 km apart, and at a background site (North Huangcheng Island) in the Bohai Sea, 50 km from the coast. A suite of neutral and ionic per- and poly-fluoroalkyl substances (PFASs) was investigated. Urban activity was related to high levels of neutral PFASs at Tianjin while perfluorooctanoic carboxylic acid (PFOA) was dominant in the atmosphere at Weifang, possibly due to industrial sources. Polyfluoroalkyl phosphoric acid diesters (diPAPs) occurred in the particle phase only, with a total concentration range of 0.02-6.72 pg m(-3). The dominant homologue was 6:2 diPAP. PFASs profiles at NHI suggested direct atmospheric transport of neutral and ionic PFASs from source regions. Temperature-dependent partitioning of fluorotelomer alcohols (FTOHS) was observed in winter, when total concentrations and particle-phase fractions of FTOHs were significantly higher as compared to those in summer. Correlation analyses suggested more active gas-phase degradation of FTOHs in summer and likely heterogeneous degradation in both seasons. Overall, it is necessary to account for ionic PFASs in both gas and particle phases and particulate matter was important for atmospheric transport and for determining the fate of PFASs, especially in areas close to a source region. (C) 2017 Elsevier Ltd. All rights reserved.</p

    Using hollow dodecahedral NiCo-LDH with multi-active sites to modify BiVO4 photoanode facilitates the photoelectrochemical water splitting performance

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    Photoelectrochemical (PEC) water splitting presents a promising approach for harnessing solar energy and converting it into hydrogen energy. However, the limited water oxidation activity of semiconductor photoanodes has severely hampered the overall conversion efficiency. In this study, a hollow dodecahedral structure of NiCo-LDH (HD-NiCo-LDH) was designed using the metal-organic framework ZIF-67 as a precursor. HD-NiCo-LDH was employed to modify the BiVO4 photoanode, serving as an oxygen evolution cocatalyst. HD-NiCo-LDH can enhance light absorption, accelerate photogenic hole extraction, promote photogenic charge separation and improve the kinetics of water oxidation reaction. Significantly, the unique hollow dodecahedral structure of HD-NiCo-LDH possesses a larger specific surface areas, which provides additional active sites for the water oxidation reaction and facilitates the adsorption of water molecules. The photocurrent density of the optimized HD-NiCo-LDH/BiVO4 photoanode reaches 4.54 mA/cm2 at 1.23 V vs. RHE, which is 3.3 times greater than the bare BiVO4 photoanode. This presented work introduces an innovative design concept for photoanodes supported by oxygen evolution cocatalysts with multi-active sites

    Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

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    Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≄30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≄90 days, chronic dialysis for ≄90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

    Key enzymes catalyzing glycerol to 1,3-propanediol

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    Can material asset reorganizations affect acquirers’ debt financing costs? – Evidence from the Chinese Merger and Acquisition Market

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    In this paper, we investigate whether material asset reorganizations (MARs), a special form of merger and acquisition (M&A) transactions, can affect the acquirers’ cost of debt financing. Further, we examine the effect of acquiring firms’ accounting information quality on the cost of debt and on the association between MARs and debt costs. We predict that compared to conventional M&As, large-scale acquisitions through MARs can generate a much greater influx of assets from target firms. This raises the acquirers’ asset collateral and thus reduces the cost of debt. Because the quality of accounting information is a key factor affecting the cost of debt, we suggest that it has a spillover effect on the debt-cost effect of MARs. Using M&A transactions by listed companies in the Chinese A-share market from 2008 to 2014 as our sample, we find that MARs are associated with a higher asset collateral and lower ex post cost of debt than conventional M&As. Furthermore, we show that the acquiring firms’ accounting information quality has a significant negative effect on debt costs, and the negative association between MARs and the cost of debt is more pronounced when accounting information quality is higher. Keywords: Material asset reorganizations, Merger and acquisition, Accounting information quality, Asset collateral, Cost of debt financin

    The potential harms of goodwill impairment avoidance: Evidence based on future performance and stock prices

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    The rapidly increasing volume of goodwill assets in the capital market generates potential risks due to the possibility of an untimely recognition of goodwill impairment. In this paper, we investigate the financial consequences of goodwill impairment avoidance based on firms' future performance and stock prices. Using Chinese A-share listed firms with goodwill balances, we find that avoiding goodwill impairments negatively affects a firm's performance growth and increases its risk of a future stock price crash. These adverse effects continue for the three years following the goodwill impairment avoidance. Our results indicate that goodwill impairment avoidance has detrimental impacts on a firm's future performance and stock price and that these impacts are persistent. Our conclusions are helpful for regulators on how to prevent the risks hidden in goodwill impairment recognition and maintain the stable development of the financial market

    Global Optimal Energy Management Strategy Research for a Plug-In Series-Parallel Hybrid Electric Bus by Using Dynamic Programming

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    Energy management strategy influences the power performance and fuel economy of plug-in hybrid electric vehicles greatly. To explore the fuel-saving potential of a plug-in hybrid electric bus (PHEB), this paper searched the global optimal energy management strategy using dynamic programming (DP) algorithm. Firstly, the simplified backward model of the PHEB was built which is necessary for DP algorithm. Then the torque and speed of engine and the torque of motor were selected as the control variables, and the battery state of charge (SOC) was selected as the state variables. The DP solution procedure was listed, and the way was presented to find all possible control variables at every state of each stage in detail. Finally, the appropriate SOC increment is determined after quantizing the state variables, and then the optimal control of long driving distance of a specific driving cycle is replaced with the optimal control of one driving cycle, which reduces the computational time significantly and keeps the precision at the same time. The simulation results show that the fuel economy of the PEHB with the optimal energy management strategy is improved by 53.7% compared with that of the conventional bus, which can be a benchmark for the assessment of other control strategies
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